POS0991 PREDICTORS OF DEVELOPMENT OF ADVANCED SPINAL ANKYLOSIS/BAMBOO SPINE IN AXIAL SPONDYLOARTHRITIS: RESULTS FROM REAL-LIFE DATA
Authors: B. Farisogullari, G. K. Yardimci, E. Bilgin, E. C. Bolek, E. Duran, G. Ayan, Z. Özsoy, G. Sandal Uzun, M. Ekici, E. Unaldi, L. Kiliç, A. Akdoğan, O. Karadag, Ş. A. Bilgen, S. Kiraz, U. Kalyoncu, A. İ. Ertenli
Journal: Annals of the Rheumatic Diseases (2022)

Background In axial spondyloarthritis (axSpA), intervertebral ossification bridges of consecutive vertebrae may progress to advanced spinal ankylosis and bamboo spine over the years [1]. Objectives To identify demographic, clinical, disease activity and treatment factors associated with development of bamboo spine / advanced spinal ankylosis and bamboo spine-only in the Hacettepe University Rheumatology Biologic Registry (HUR-BIO) cohort. Methods HUR-BIO is a prospective, single center database of biological disease-modifying antirheumatic drug (bDMARD) treatments. 770 patients on bDMARDs treatment had both lumbar and cervical lateral radiographies at the time of the data collection, and were included in the study. Bamboo spine was defined Bath Ankylosing Spondylitis Radiologic Index (BASRI)-spine grade 4 with a complete fusion of lumbar and cervical spines. Advanced spinal ankylosis was defined as the presence of at least two intervertebral adjacent bridges and/or fusion at the lumbar and/or cervical spine without bamboo spine. We analyzed the ensemble of variables by multivariable logistic regression to identify predictors associated with bamboo spine / advanced spinal disease, and bamboo spine-only. Results In the study, there were 99 patients with advanced spinal ankylosis and 78 patients with bamboo spine. Older age (OR 1.12, 95% CI 1.07-1.17), male gender (OR 4.26, 95% CI 1.75-10.41), delay diagnosis ≥ 24 months (OR 2.7, 95% CI 1.27-5.74), obesity (OR 4.03, 95% CI 1.53-10.64), hip involvement (OR 4.94, 95% CI 1.94-12.6), smoking ≥ 10 package/year (OR 2.28, 95% CI 1.003-5.2) were significantly associated factors with bamboo spine / advanced spinal ankylosis. Similarly, older age (OR 1.17, 95% CI 1.09-1.3), male gender (OR 8.31, 95% CI 2.09-33.1), obesity (OR 5.15, 95% CI 1.25-21.27), hip involvement (OR 4.74, 95% CI 1.32-16.96) and smoking ≥ 10 package/year (OR 3.19, 95% CI 1.03-9.89) were showed statistical significance with bamboo spine (Table 1). Table 1. Predictors of Bamboo Spine and Advanced Spinal Ankyloses, and Bamboo Spine-only Multivariable Model Covariates Bamboo Spine and Advanced Spinal Ankylosis Bamboo Spine OR (95% CI ) p-value OR (95% CI ) p-value Age 1.12 (1.07-1.17) &lt;0.001* 1.17 (1.09-1.3) &lt;0.001* Male (vs female ) 4.26 (1.75-10.41) 0.001* 8.31 (2.09-33.1) 0.003* Delay Diagnosis (≥ 24 months vs &lt;24 months ) 2.7 (1.27-5.74) 0.01* 2.39 (0.85-6.71) 0.09 BMI 0.019* 0.074 - 25 to &lt; 30 (vs &lt;25 ) 2.05 (0.77-5.46) 0.15 3.37 (0.84-13.6) 0.087 - ≥ 30 (vs &lt;25 ) 4.03 (1.53-10.64) 0.005* 5.15 (1.25-21.27) 0.024* Hip involvement (present vs absent ) 4.94 (1.94-12.6) 0.001* 4.74 (1.32-16.96) 0.017 Smoking (≥ 10 package/year vs &lt;10 package/year ) 2.28 (1.003-5.2) 0.049* 3.19 (1.03-9.89) 0.044* Family History of SpA (First-degree; present vs absent ) 1.67 (0.61-4.57) 0.32 2.82 (0.79-10.06) 0.11 Uveitis History (present vs absent ) 1.04 (0.39-2.74) 0.94 1.19 (0.33-4.29) 0.79 Use SSZ (present vs absent ) 0.6 (0.17-2.07) 0.42 2.09 (0.39-11.28) 0.39 Use Corticosteroids (present vs absent ) 0.69 (0.27-1.75) 0.43 0.73 (0.18-2.97) 0.66 *p &lt;0.05 BMI: Body mass index; SpA: Spondyloarthritis; SSZ: Sulfasalazine Conclusion Data on the predictors of development of advanced spinal ankylosis and bamboo spine are scarce. In this study, we showed that older age, male gender, delay in diagnosis, obesity, hip involvement and smoking are factors that predict the development of advanced spinal involvement in axSpA. References [1]Ostergaard M, Lambert RG. Imaging in ankylosing spondylitis. Ther Adv Musculoskelet Dis. 2012;4(4):301-11. Disclosure of Interests None declared